Hybrid polymer and uses thereof

Abstract

The invention relates to a hybrid polymer obtained by a free-radical precipitation polymerization process from at least one monomer comprising at least one unsaturated ethylenic function, in the presence of at least one protein. The invention is also directed to the use of said hybrid polymer as a viscosifying agent in various formulations or compositions.

Description

DescriptionTitle: HYBRID POLYMER AND USES THEREOFTechnical field

[0001] The invention belongs to the technical field of hybrid polymers. More precisely, a subject of the invention is a hybrid polymer obtained by a free-radical precipitation polymerization process from at least one monomer comprising at least one unsaturated ethylenic function, in the presence of at least one protein. The invention is also directed to the use of said hybrid polymer as a viscosifying agent in various formulations or compositions.Prior art

[0002] Synthetic polymers have been used for many years as viscosifying agents in a number of fields of application for increasing the viscosity of various aqueous preparations.

[0003] These polymers have unmatched application performance qualities, however they are 100% derived from fossil resources. A recent shortage of monomers for producing these synthetic polymers has been observed due to increasing demand and insufficient crude oil reserves. There is therefore the need to replace these synthetic polymers with hybrid polymers which are at least partially derived from renewable natural sources. These hybrid polymers retain optimum application characteristics.

[0004] The grafting of natural materials such as sugars and starches with monomers is already described in the literature. For example, U.S. Pat. 5,854,191, 5,223,171, 5,227,446 and 5,296,470 disclose the use of graft copolymers in cleaning applications. Patents WO / 18108663-65-67 for their part describe the use of such hybrids for cosmetic compositions.

[0005] These hybrid thickening polymers are a good alternative, however their use remains highly specific to a given application field. They are not compatible with applications having more difficult experimental conditions, such as the petroleum application for example, which requires the polymer to withstand high temperatures.

[0006] Thus, it is more than necessary to develop a universal viscosifying agent that meets the expected application characteristics in various fields of application.

[0007] Unexpectedly, the Applicant Company has developed a hybrid polymer obtained by free- radical precipitation polymerization which remedies the abovementioned disadvantages.Summary

[0008] The present application relates to a hybrid polymer obtained by a free-radical precipitation polymerization process among at least one monomer comprising at least one unsaturated ethylenic function, and in the presence of at least one protein.

[0009] More specifically, the invention relates to a hybrid polymer (HP) in particulate form. This hybrid polymer (HP) is obtained by a free-radical precipitation polymerization process according to the following successive steps:(A) preparing a solution (SI) comprising:- 50% to 95% by weight of at least one polar solvent,- 4% to 40% by weight of at least one monomer comprising at least one unsaturated ethylenic function, and- 0.1% to 40% by weight of at least one protein; the percentages being given relative to the total weight of (SI), and totalling 100%;(B) initiating polymerization in the solution (SI) in order to obtain a dispersion (DI) comprising at least one hybrid polymer (HP), said polymer (HP) precipitating in the polymerization solvent;(C) isolating the hybrid polymer (HP), in particulate form, from the dispersion (DI).

[0010] The invention also relates to the use of said hybrid polymer (HP) as a viscosifying agent. The invention also relates to a viscosity modifying agent comprising at least one hybrid polymer (HP) according to the invention.Brief description of the drawingsFig. l

[0011] [Fig. 1] illustrates the NMR / DOSY spectrum of the serum protein alone.Fig. 2

[0012] [Fig. 2] illustrates the NMR / DOSY spectrum of the hybrid polymer (HP).Description of the embodiments

[0013] Definitions and generalities

[0014] Throughout the present application, the following definitions apply unless specifically indicated otherwise.

[0015] All intervals are inclusive and combinable. The value ranges include the lower and upper limits. Thus, the ranges of values "between 0.1 and 1.0" and "from 0.1 to 1" include the values 0.1 and 1.0. The number of significant figures does not constitute a limitation of the amounts indicated or a limitation of the accuracy of the data.

[0016] As used herein, the term "hydrophilic monomer" denotes a monomer the octanol / water partition coefficient, Kow, of which is less than 1, determined at a temperature of 25°C and with a pH of between 6 and 8.

[0017] As used herein, the term "hydrophobic monomer" denotes a monomer the octanol / water partition coefficient, Kow, of which is greater than 1, this being determined at a temperature of 25 °C and with a pH of between 6 and 8.

[0018] The partition coefficient Kow is defined as follows:

[0019] [Math. 1][monomer] octanol Kow = — - - -[monomer] water

[0020] With [monomer e] octanol = monomer solubility equilibrium concentration in g / L in n- octanol [monomer e]eau = equilibrium monomer concentration in g / L in water.

[0021] According to the present invention, the weight-average molecular weight of the synthetic polymers according to the invention is determined by measuring the intrinsic viscosity. The intrinsic viscosity can be measured by methods known to those skilled in the art and can in particular be calculated from the values of reduced viscosity for various concentrations by a graphical method consisting in plotting the values of reduced viscosity (on the y-axis) as a function of the concentrations (on the x-axis) and extrapolating the curve to zero concentration. The intrinsic viscosity value is read on the y-axis or using the least squares method. Then, the weight-average molecular weight can be determined by the well-known Mark-Houwink equation:

[0022] [r|] = K.M“

[0023] [q] represents the intrinsic viscosity of the polymer determined by the method for measuring the viscosity in solution,K represents an empirical constant,M represents the molecular weight of the polymer, a represents the Mark-Houwink coefficient, a and K depend on the particular polymer-solvent system. Tables known to those skilled in the art give the values for a and K according to the polymer-solvent system.

[0024] According to the present invention, the abovementioned monomers comprising at least one unsaturated ethylenic function can polymerize with one another to form polymers. The term "polymer" denotes a product formed by the polymerization of two or more monomers. Polymers made from a single monomer type are called homopolymers. Polymers consisting of two or more different monomer types are called copolymers.

[0025] As used here, the term "water-soluble polymer" denotes a polymer which gives an aqueous solution without insoluble particles when it is dissolved with stirring for 4 hours at 25 °C at a concentration of 2 g.L1in deionized water.

[0026] An "anionic polymer" means a polymer containing anionic monomers and optionally nonionic monomers. A "nonionic polymer" means a polymer containing only nonionic monomers.

[0027] An amphoteric polymer is a polymer comprising cationic charges and anionic charges, preferentially as many anionic charges as cationic charges; it may also contain a nonionic monomer.

[0028] The term "particle size" denotes the mean size, by number, of the particles of water-soluble polymer. It corresponds to the largest dimension, for example the diameter for spherical particles, preferentially measured with a laser measuring apparatus using conventional techniques that form part of the knowledge of those skilled in the art. An apparatus of Mastersizer type from Malvern, for example the MS2000 apparatus, may be used for this purpose. This type of apparatus makes it possible to measure, by laser diffraction, the particle size distribution of the particles in liquid medium or in solid form.

[0029] The term "monomer unit" denotes the chemical unit relating to the corresponding monomer when it is polymerized in the polymer chain of the polymer.

[0030] The term "protein unit" denotes the chemical unit relating to a corresponding protein when it is grafted into the polymer chain of the polymer.

[0031] The invention thus relates to a hybrid polymer (HP) in particulate form obtained by a free- radical precipitation polymerization process according to the following successive steps:(A) preparing a solution (SI) comprising:- 50% to 95% by weight of at least one polar solvent,- 4% to 40% by weight of at least one monomer comprising at least one unsaturated ethylenic function, and- 0.1% to 40% by weight of at least one protein; the percentages being given relative to the total weight of (SI), and totalling 100%;(B) initiating polymerization in the solution (SI) in order to obtain a dispersion (DI) comprising at least one hybrid polymer (HP), said polymer (HP) precipitating in the polymerization solvent;(C) isolating the hybrid polymer (HP), in particulate form, from the dispersion (DI).

[0032] The solution (SI) is preferentially produced by first mixing the monomer(s) having at least one unsaturated ethylenic function and at least one polar solvent, and then subsequently adding the protein(s) to this mixture.

[0033] The monomer(s) comprising at least one unsaturated ethylenic function of step (A) are preferentially hydrophilic monomers.

[0034] The hydrophilic monomer(s) are preferentially nonionic and / or anionic, such that when they are nonionic they are selected from acrylamide, methacrylamide, N,N-dimethylacrylamide, N- vinylformamide, N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone, acryloylmorpholine(ACMO), diacetone acrylamide, or a mixture of these monomers, and when they are anionic they are selected from the group comprising monomers possessing a carboxylic acid function and salts thereof, monomers possessing a sulfonic acid function and salts thereof or monomers possessing a phosphonic function and salts thereof, or a mixture of these monomers.

[0035] The solution (SI) preferentially comprises from 10% to 30% by weight of at least one hydrophilic monomer, the percentage being given relative to the total weight of the solution (SI).

[0036] In step (A) the solution (SI) is preferentially prepared from a mixture of polar solvents and at least one monomer comprising at least one unsaturated ethylenic function, said mixture of polar solvents comprising 0.5% to 10% by weight of water, and at least 90% by weight of an alcohol comprising 1 to 4 carbons. The alcohol comprising 1 to 4 carbons is preferentially tert-butanol. The mixture of polar solvents preferentially comprises from 1% to 5% by weight of water and from 95% to 99% by weight of tert-butanol.

[0037] The protein is preferentially selected from proteins of animal origin, plant origin and / or mixtures thereof. The protein is preferentially a casein, a serum protein, a wheat protein or mixtures thereof.

[0038] The hybrid polymer (HP) preferentially comprises monomer units of at least one monomer comprising at least one unsaturated ethylenic function, and protein units, said monomer units and said protein units being partially or totally linked by at least one covalent bond.

[0039] The hybrid polymer (HP) preferentially has a weight-average molecular weight of between 200 000 and 2 000 000 daltons.

[0040] The invention also relates to the use of the hybrid polymer (HP) according to the invention as a viscosifying agent in the recovery of hydrocarbons; in the drilling and cementing of wells; in the stimulation of hydrocarbon wells; in paper manufacture; in construction; in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; or in the manufacture of textiles.

[0041] The invention also relates to a viscosifying agent comprising at least one hybrid polymer (HP) according to the invention, in the recovery of hydrocarbons; in the drilling and cementing of wells; in the stimulation of hydrocarbon wells; in paper manufacture; in construction; in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; or in the manufacture of textiles.

[0042] The invention also relates to an aqueous composition thickened with a hybrid polymer (HP) according to the invention.

[0043] Monomers comprising at least one unsaturated ethylenic function

[0044] The hybrid polymer (HP) according to the invention is obtained by precipitation polymerization of monomers comprising at least one unsaturated ethylenic function and in the presence of at least one protein.

[0045] Preferentially, the solution (SI) comprises between 4% to 40% by weight of monomers comprising at least one unsaturated ethylenic function, more preferentially still from 10% to 30%, the percentages by weight being given relative to the total percentage by weight of the solution (SI).

[0046] Said monomers may be synthetic and / or biobased in nature.

[0047] Advantageously, these monomers are preferentially hydrophilic monomers. The hydrophilic monomers are nonionic, anionic, cationic or zwitterionic. Preferably, these monomers have a single ethylenic unsaturation (double bond between two carbon atoms).

[0048] Advantageously, the nonionic monomer(s) that can be used in the context of the invention are selected, in particular, from the group comprising water-soluble vinyl monomers, such as acrylamide, methacrylamide, N-alkylacrylamides, N-alkylmethacrylamides, N,N- dialkylacrylamides (for example, N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N- dialkyhnethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinylcaprolactam, N-vinylformamide (NVF), N-vinylacetamide, N-vinylimidazole, N-vinylsuccinimide, acryloylmorpholine (ACMO), , glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylates, thioalkyl (meth)acrylates, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylates and its alkoxylated derivatives, hydroxyethyl (meth)acrylates and its alkoxylated derivatives, hydroxypropylacrylate and its alkoxylated derivatives, vinyl acetate, and mixtures thereof. Among these nonionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C1-C3, alkyl groups. They are preferentially linear alkyls. Preferentially, the nonionic monomer is acrylamide.

[0049] The solution (SI) advantageously comprises between 1 and 99 mol% of nonionic monomer(s), preferentially between 2 and 70 mol%, the molar percentage being expressed relative to the total number of moles of monomers in the solution (SI).

[0050] Advantageously, the anionic monomer(s) can be selected from a large group. These monomers may have vinyl, acrylic, maleic, fumaric, malonic, itaconic, or allyl functions, and contain a carboxylate, phosphonate, phosphate, sulfate, or sulfonate group, or another anionically charged group. Examples of suitable monomers include acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; crotonic acid; maleic acid; fumaric acid; acrylamidoundecanoic acid; 3-acrylamido-3- methylbutanoic acid; maleic anhydride; monomers of the strong acid type having for example a sulfonic acid or a phosphonic acid type function, such as vinylsulfonic acid, vinylphosphonic acid,allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-l,3-disulfonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropyl acrylate, allylphosphonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2- methylpropanedisulfonic acid; water-soluble salts of these monomers such as their alkali metal salts (different from the crystalline form of the sodium salt of 2-acrylamido-2 -methylpropanesulfonic acid), alkaline earth metal salts, or ammonium salts; and mixtures thereof. Preferentially, the anionic monomer(s) is / are acrylic acid and / or salts thereof.

[0051] The solution (SI) advantageously comprises between 1 and 99 mol% of anionic monomer(s), preferentially between 2 and 70 mol%, more preferentially between 3 and 50 mol%, the molar percentage being expressed relative to the total number of moles of monomers in the solution (SI).

[0052] According to one aspect of the invention, the carboxylic acid functions of the anionic monomer are salified with a salification agent, also referred to as a neutralization agent. The term "salified" is understood to mean that at least one acid function of the anionic monomer is replaced by a salt neutralizing the negative charge of the acid function. In other words, the non-salified form corresponds to the acid form of the monomer, for example R-C(=O)-OH in the case of the carboxylic acid function, while the neutralized form of the monomer corresponds to the form R-C(=O)O- X+, X+ corresponding to a positively charged ion. The neutralization of the acid functions can be partial or total.

[0053] Generally, salification is performed before the polymerization.

[0054] In one particular embodiment of the invention, between 30 to 100 mol% of the acid functions are salified, more advantageously between 60 and 100 mol%.

[0055] The salification agent is advantageously a Bronsted base. It is preferably selected from ammonia, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, and mixtures thereof. Ammonia is most particularly preferred.

[0056] Advantageously, the cationic monomer(s) which can be used in the context of the invention are selected from monomers derived from units of vinyl type, in particular acrylamide, acrylic, allyl or maleic type, these monomers possessing a phosphonium or quaternary ammonium function. Mention may be made, in particular and in a non-limiting manner, of aminoalkyl (meth)acrylate, quatemized dimethylaminoethyl acrylate (DMAEA), quatemized dimethylaminoethyl methacrylate (DMAEMA), dimethyldiallylammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC) and methacrylamidopropyltrimethylammonium chloride (MAPTAC). The quatemization agent can be selected from alkyl chlorides, dialkyl sulfates or alkyl halides. Preferentially, the quatemization agent is selected from methyl chloride and diethyl sulfate.

[0057] The solution (SI) advantageously comprises between 5 and 35 mol% of cationic monomer(s), the molar percentage being expressed relative to the total number of moles of monomers in the solution (SI).

[0058] Those skilled in the art will know how to prepare the quatemized monomers, for example by means of alkyl halide of the type R*-X, R* being an alkyl group and X being a halogen (in particular methyl chloride). In addition, the present invention also covers monomers of the DADMAC, APTAC and MAPTAC type in which the halide counterion is fluoride, bromide or iodide instead of chloride.

[0059] Advantageously, the zwitterionic monomer(s) can be a derivative of a unit of vinyl type, in particular acrylamide, acrylic, allyl or maleic type, this monomer possessing an amine or quaternary ammonium function and an acid function of carboxylic (or carboxylate), sulfonic (or sulfonate) or phosphoric (or phosphate) type. Mention may be made, in particular and in a non-limiting manner, of derivatives of dimethylaminoethyl acrylate, such as 2-((2- (acryloyloxy)ethyl)dimethylammonio)ethane-l -sulfonate, 3-((2-(acryloyloxy)ethyl)dimethylammonio)propane- 1 -sulfonate, 4-((2-(acryloyloxy)ethyl)dimethylammonio)butane- 1 -sulfonate, [2-(acryloyloxy)ethyl](dimethylammonio)acetate, derivatives of dimethylaminoethyl methacrylate such as 2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethane-l-sulfonate, 3-((2- (methacryloyloxy)ethyl)dimethylammonio)propane- 1 -sulfonate, 4-((2-(methacryloyloxy)ethyl)dimethylammonio)butane- 1 -sulfonate, [2-(methacryloyloxy)ethyl](dimethylammonio)acetate, derivatives of dimethylaminopropylacrylamide such as 2-((3-acrylamidopropyl)dimethylammonio)ethane-l-sulfonate, 3-((3- acrylamidopropyl)dimethylammonio)propane- 1 -sulfonate, 4-((3- acrylamidopropyl)dimethylammonio)butane- 1 -sulfonate, [3- (acryloyloxy )propyl](dimethylammonio)acetate, derivatives of dimethylaminopropylmethylacrylamide such as 2-((3- methacrylamidopropyl)dimethylammonio)ethane- 1 -sulfonate, 3-((3- methacrylamidopropyl)dimethylammonio)propane- 1 -sulfonate, 4-((3- methacrylamidopropyl)dimethylammonio)butane- 1 -sulfonate and [3- (methacryloyloxy )propyl](dimethylammonio)acetate, and mixtures thereof.

[0060] Preferred hydrophilic monomers are acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS) or a mixture thereof, N-vinylpyrrolidone (NVP), MADC, ADC and acrylamide.

[0061] According to one aspect of the invention, the monomers having an ethylenic function, in addition to being selected from hydrophilic monomers as described above, can also be selected from hydrophobic monomers.

[0062] The hydrophobic monomers, the partition coefficient Kow of which is greater than 1, are preferably selected from the following lists.- esters of (meth)acrylic acid having alkyl, arylalkyl and / or ethoxylated and / or propoxylated chain; derivatives of (meth)acrylamide having alkyl, arylalkyl or dialkyl and / or ethoxylated and / or propoxylated chain; cationic allyl derivatives having alkyl, arylalkyl or dialkyl chain and / or ethoxylated and / or propoxylated chain; hydrophobic anionic or cationic (meth)acryloyl derivatives; and anionic or cationic monomer derivatives of (meth)acrylamide bearing a hydrophobic chain. The alkyl groups of these hydrophobic monomers are preferably C6 to C24 alkyl groups. The most preferred monomers are the bromoalkylated derivatives of methacrylamidodimethylaminopropyl with a C8-C16 alkyl chain and ethoxylated behenyl methacrylate.- n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl(meth)acrylamide, lauryl (meth)acrylate, lauryl(meth)acrylamide, myristyl (meth)acrylate, myristyl(meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl(meth)acrylamide, cetyl (meth)acrylate, cetyl(meth)acrylamide, oleyl (meth)acrylate, oleyl(meth)acrylamide, erucyl (meth)acrylate, erucyl(meth)acrylamide, and combinations thereof.- LCST (Lower Critical Solution Temperature) and / or UCST (Upper Critical Solution Temperature) monomers or macromonomers. In other words, the hydrophobic nature may originate from the LCST and / or from the properties of the monomers or macromonomers. Patent application W02020 / 094960 Al refers to such macromonomers having the LCST property.Other zwitterionic monomers are described by the applicant in document WO21123599.

[0063] Among these hydrophobic monomers:- the alkyl groups are preferably C3-C20, more preferentially C3-C8, alkyl groups. The C6-C20 alkyls are preferably linear alkyls while the C3-C5 alkyls are preferably branched,- the arylalkyl groups are preferably C7-C25, more preferably C7-C15, arylalkyl groups,- the ethoxylated chains preferably comprise 6 to 100 -CH2-CH2-O- groups, more preferentially 10 to 40,- the propoxylated chains preferably comprise 1 to 50 -CH2-CH2-CH2-O- groups, more preferably 1 to 20.

[0064] The preferred hydrophobic monomers are selected from N-isopropylacrylamide; N,N- dimethylacrylamide; N,N-diethylacrylamide; N-tert-butylacrylamide; N-vinylcaprolactam; and diacetone acrylamide.

[0065] According to this aspect of the invention, the concentration of hydrophobic monomers is preferably between 0.0001 and 10 mol%, more preferentially between 0.001 and 5 mol%, more preferentially still between 0.01 and 3 mol%, more preferentially still between 0. 1 and 2 mol%, more preferentially still between 0.2 and 1.5 mol%, more preferentially still between 0.3 and 1.3 mol%,the molar percentage being expressed relative to the total number of moles of monomers in the solution (SI).

[0066] If hydrophobic monomers are added during the precipitation polymerization, the hydrophilic monomers will preferentially be selected from anionic and / or nonionic hydrophilic monomers.

[0067] The amounts of the various monomer(s) will be adjusted by those skilled in the art so as not to exceed 100 mol% during the preparation of the water-soluble polymers according to the invention.

[0068] Protein

[0069] The hybrid polymer (HP) according to the invention is obtained from at least one protein. It can also be obtained from a plurality of proteins of differing nature.

[0070] The protein(s) are added to the polymerization feedstock, in the solution (SI) in step (A) of the process described in the present application.

[0071] The proteins are obtained by conventional methods known to those skilled in the art, for example by dissolution, milling, screening and classification. The protein(s) can be added in solid or liquid form to the solution (SI). Advantageously, the proteins are added in powder form.

[0072] According to the invention, the solution (SI) comprises from 0.1% to 40% by weight of proteins, preferentially between 1% and 20%, more preferentially between 2% and 15% by weight, more preferentially still between 5% and 10%.

[0073] The term "protein" is used here to include both native (or chemically unmodified) proteins and modified proteins. The term "modified proteins" means a protein that has undergone one or more pretreatments. These pretreatments can be of physical nature by shearing, chemical nature by acid or alkaline hydrolysis and / or enzymatic nature via a protease.

[0074] Advantageously, native proteins are preferred.

[0075] The protein(s) according to the invention can be of animal origin, and examples of animal proteins which may be mentioned include: milk proteins such as [3-lactoglobulin, casein, whey; serum proteins such as horse serum; placental proteins; fibrous dermal proteins such as collagen, elastin, silk proteins.

[0076] The protein(s) according to the invention can be of plant origin, such as maize, wheat, barley and oats, soybean, peas, for example, glutelin, prolamin, zein and gluten. Advantageously, the plant proteins are selected from soy proteins, wheat proteins, oat proteins, pea proteins. The proteins can be obtained from seeds, for example soybean, cotton seeds, peanuts, sunflower, rapeseed, coconut, flax seeds, sesame, safflower, peas, beans and lentils.

[0077] Other sources of proteins are bacteria, fungi, algae and yeasts, for example Pseudomonas, Lactobacillus, Penicillium, E. coli, blue-green algae, green algae, Chlorella, Spirulina and spent yeasts.

[0078] Preferentially, the protein selected will be a casein, a serum protein or wheat protein.

[0079] In order to transform the proteins into a soluble form, it is often necessary to perform digestion by physical, chemical or enzymatic treatment, for example hydrolysis with an acid or alkali, fermentation with yeasts, bacteria or enzymes, extraction methods to remove minor constituents, coagulation from extracts by heating, addition of electrolyte, pH adjustment or addition of precipitants. The pure products can be prepared, for example, by fractional dissolution and precipitation or by dialysis.

[0080] The protein(s) used according to the invention are water-soluble or water-insoluble. This has no effect at all on the viscosifying efficacy of the final hybrid polymer (HP). However, the choice of protein solubility is of real interest for the application aspect. If the aim is to obtain a viscous gel especially for cosmetic applications, a translucent gel will be preferred, and a soluble protein will be preferred in this case. If the transparency of the application gel does not matter, an insoluble protein can be selected.

[0081] The proteins can be present in the form of a mixture. This means a mixture containing a plurality of proteins originating from the same living kingdom or from different kingdoms. For example, a mixture containing a plurality proteins of animal origin, or a mixture containing at least one protein of animal origin and at least one protein of plant origin and / or one protein of bacterial origin.

[0082] Preferentially, a single protein is added to the polymerization feedstock of step (A).

[0083] Polymerization

[0084] Precipitation polymerization in a solvent medium consists in the polymerization of monomers soluble in a solvent, while the polymer obtained is itself insoluble and thus precipitates in this solvent. Once the polymerization is complete, the polymer appears in the reaction medium in the form of a precipitate. The hybrid polymer (HP) precipitates in the polymerization solvent. The hybrid polymer (HP) precipitation occurs during the polymerization step. It does not occur after the polymerization step. More precisely, the hybrid polymer (HP) precipitation occurs when the hybrid polymer (HP) reaches a certain polymerization degree. At the beginning of the polymerization, the polymerization, the hybrid polymer (HP) is soluble in the reaction solvent, its polymerization degree increases such as the length of the polymer chain. During polymerization, above a certain polymerization degree, the hybrid polymer (HP) becomes insoluble in the polymerization solvent and the hybrid polymer (HP) precipitates. The polymerization continues until its end.

[0085] The hybrid polymer (HP) results from the polymerization between at least one monomer comprising at least one unsaturated ethylenic function and at least one protein. According to the present invention, the hybrid polymer (HP) is polymerized by free-radical precipitation polymerization in a polar solvent medium.

[0086] For step (A) of the process, a solution (SI) is prepared by including 4% to 40% by weight of at least one monomer having an unsaturated ethylenic function, as described above, 60% to 95% by weight of at least one polar solvent, and from 0.1% to 40% by weight of at least one protein; the percentages being given relative to the total weight of (SI), and totalling 100%.

[0087] According to a preferred embodiment, the solution (SI) is produced by first mixing the monomers having an unsaturated ethylenic function and at least one polar solvent, and then subsequently adding the protein(s) to this mixture.

[0088] According to the invention, it is possible to use a polar solvent or a mixture of polar solvents. The mixture of polar solvents preferentially comprises water and an alcohol or a ketone.

[0089] The alcohol or ketone is preferentially selected from methanol, ethanol, 1 -propanol, 2- propanol, 2-methyl-2 -propanol, 1 butanol, 2-butanol, dimethyl ketone, diethyl ketone, pentan-2 -one, butanone, tetrahydropyran, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3 -dioxane, 1,4-dioxane. The mixture of polar solvents is preferably a mixture of protic solvents (proton donors).

[0090] In one particular embodiment of the invention, the solvent used for the precipitation polymerization is preferentially an alcohol comprising 1 to 4 carbons. It is advantageously selected from methanol, ethanol, propan- l-ol, isopropanol, tert-butanol or mixtures thereof. Preferentially, the solvent used is solely tert-butanol.

[0091] The mixture of polar solvents preferentially contains up to 10% by weight of water, preferentially between 1% to 6% by weight of water and more preferentially still between 2% to 4% by weight of water.

[0092] The mixture of polar solvents preferentially contains at least 90% by weight of alcohol, more preferentially at least 95% by weight, more preferentially still at least 97% by weight of alcohol.

[0093] Thus, preferentially, the mixture of polar solvents that is used for the precipitation polymerization contains less than 10% by weight of water and at least 90% by weight of tert-butanol, preferentially 1% to 5% by weight of water and 99% to 95% by weight of tert-butanol, more preferentially still 2.5% by weight of water and 97.5% of tert-butanol.

[0094] The polymerization is preferentially carried out in the absence of oxygen, according to the present invention. Degassing consists in removing residual oxygen from the solution (SI) obtained at the end of step (A). To do this, an inert gas is introduced so as to degas the solution (S 1). The inertgas is usually passed through the solution. Inert gases suitable for this purpose are, for example, nitrogen or carbon dioxide.

[0095] According to one aspect of the invention, surfactants are added in order to stabilize the medium in order to obtain optimal polymerization conditions. The solution (SI) can comprise at least one surfactant having an HLB (hydrophilic-lipophilic balance) of less than 15, preferentially of between 9-13, in order to stabilize said solution SI and improve the polymerization. Generally, the amount of said surfactant in the solution (SI) is between 0.2% and 20% by weight, preferentially from l% to 10%.

[0096] The hydrophilic-lipophilic balance (HLB) of a chemical compound is a measure of its hydrophilic and / or lipophilic properties, determined by calculating the values for the different regions of the molecule, as described by Griffin in 1949.

[0097] The surfactant may be nonionic, anionic, cationic, amphoteric, zwitterionic, preferentially it is a nonionic surfactant. The surfactant(s) is / are preferentially selected from ethoxylated surfactants, PEG diacrylates, ethers of ethoxylated fatty alcohol type, saccharide or polyhydric alcohol esters or betaines, esters prepared on the basis of alcohol of glycerol, diglycerol, or triglycerol type or other alcohols such as saccharides such as maltitol or sorbitol and mixtures thereof. Advantageously, alkyl polyglucosides are used.

[0098] According to one aspect of the invention, a crosslinking agent may be included in the solution (SI). The crosslinking agent is advantageously selected from polyfimctional agents such as methylenebisacrylamide (MBA), ethylene glycol diacrylate, polyethylene glycol dimethacrylate, diacrylamide, cyanomethyl acrylate, vinyloxy ethyl acrylate, vinyloxy methacrylate, triallylamine, trimethylolpropane triacrylate (TMPTA), tetraallylammonium chloride (TAAC), formaldehyde, glyoxal, glycidyl ethers such as ethylene glycol diglycidyl ether, epoxides and mixtures thereof. Preferentially, the crosslinking agent is trimethylolpropane triacrylate (TMPTA).

[0099] The solution (SI) preferentially comprises between 500 ppm and 5000 ppm by weight, relative to the total weight of the solution (SI), of crosslinking agent, more preferentially between 1600 and 3700 ppm, more preferentially still between 2500 and 3200 ppm by weight.

[0100] According to the process of the invention, the polymerization is initiated using free radical initiators with one or more of the above hydrophilic and / or hydrophobic monomers, and the protein(s). As examples of free radical initiator agents, mention may be made of redox pairs with, among the oxidizing agents, cumene hydroperoxide or tertiary butyl hydroxyperoxide, and among the reducing agents, persulfates such as sodium metabisulfite and Mohr's salt. Azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile) and 2,2'-azobis(2- amidinopropane) hydrochloride may also be used in the same way as peroxide compounds such as benzoyl peroxide, tert-butyl hydroperoxide or lauroyl peroxide.

[0101] The degassing is stopped before starting the polymerization under reflux for several hours, preferentially for at least 2 hours.

[0102] According to the present invention, the free-radical precipitation polymerization takes place at a temperature of between 60 and 85°C at atmospheric pressure.

[0103] Step (B) of the process consists in initiating the polymerization of the solution (SI) in order to obtain a dispersion (DI) comprising a hybrid polymer (HP). The polymer (HP) is in the form of a precipitate. Step (C) of the process consists in isolating the hybrid polymer (HP) in particulate form. Said hybrid polymer (HP) can be easily isolated using the usual separation, evaporation and drying processes known to those skilled in the art. The solvent may be extracted by fdtration or distillation, advantageously by distillation.

[0104] The hybrid polymer (HP) is then recovered in particulate form. Generally, the size of the particles of the hybrid polymer (HP) is advantageously between 5 nm and 5 mm, more advantageously between 50 nm and 5 mm, preferentially between 100 nm and 2 mm, more preferentially still between 200 pm and 1 mm. It may in particular be between 50 nm and 1 mm, or between 500 pm and 5 mm, or between 5 pm and 1 mm, or alternatively between 100 pm and 1 mm.

[0105] Hybrid polymer

[0106] The hybrid polymer (HP) has a weight-average molecular weight advantageously of between 200 000 and 2 000 000 daltons, preferentially between 300 000 and 1 500 000 daltons.

[0107] The hybrid polymer (HP) has a Brookfield viscosity preferentially of between 1000 and 100 000 cPs, more preferentially between 2500 and 75 000 cPs, more preferentially between 5000 and 50 000 cPs. The Brookfield viscosity is measured on a 1% by weight solution of polymer in water with a Brookfield RVT unit viscometer with a rotational speed of 20 rpm.

[0108] The hybrid polymer (HP) can be linear, structured, or branched. Preferentially, the (HP) is structured, i.e. in star-branched or comb form.

[0109] The hybrid polymer (HP) comprises less than 40% by mass of protein, preferentially from 10% to 40% by mass of protein, more preferentially still from 15% to 35% by mass of protein.

[0110] In the hybrid polymer (HP), the weight ratio between the monomer units and the protein units is preferentially between 50 / 1 and 1 / 5, preferentially between 25 / 1 and 1 / 3, more preferentially between 10 / 1 and 1 / 2, more preferentially between 6 / 1 and 1 / 1.

[0111] The NMR / DOSY analysis of Fig. 1 makes it possible to observe that the hybrid polymer (HP), according to the present invention, has at least partially covalent bonds between the protein and the monomers comprising at least one ethylenic function.

[0112] This analysis makes it possible to conclude that the hybrid polymer (HP) according to the present invention is present in a mixture comprising at least: the hybrid polymer (HP) having at least partially covalent bonds between the protein and the monomers comprising at least one ethylenic function, monomers comprising at least one ethylenic function having reacted with one other to form water-soluble polymers and lone proteins.

[0113] D2O and TSP-d4 are deuterated NMR solvents. They make it possible to dissolve the product to be analysed without producing a signal. This is because, since the solvents are generally present in very large excess, their peaks would hinder the reading of the NMR spectrum.

[0114] Use of the hybrid polymer in various applications

[0115] The invention also relates to the use of the hybrid polymer (HP) as a viscosifying agent in the recovery of hydrocarbons (petroleum and / or gas); in the drilling and cementing of wells; in the treatment of water in open, closed or semi-closed circuit; in the treatment of fermentation musts in the treatment of sludges; in paper manufacture; in construction; in the treatment of wood; in the treatment of hydraulic compositions (concrete, cement, mortar and aggregates); in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; in the manufacture of textile printing pastes; in the manufacture of battery components; in geothermal applications; in the manufacture of hygiene layers; or in agriculture.

[0116] Advantageously, the invention relates to the use of the hybrid polymer (HP) according to the invention in the manufacture of cosmetic compositions as a thickener (thickening agent), conditioner (conditioning agent), stabilizer (stabilizing agent), emulsifier (emulsifying agent), fixer (fixing agent) or film former (film -forming agent).

[0117] The invention also relates to the use of the hybrid polymer (HP) as a viscosifying agent for a pigment composition used in textile printing, said agent comprising at least one hybrid polymer according to the invention.

[0118] The invention also relates to a process for the enhanced recovery of petroleum or gas by flushing a subterranean formation, comprising the use of at least one hybrid polymer (HP) according to the invention.

[0119] The invention also relates to a viscosifying agent comprising at least one hybrid polymer (HP) according to the invention in a field selected from the recovery of hydrocarbons; in the drilling and cementing of wells; in the stimulation of hydrocarbon wells; in paper manufacture; in construction; in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; in the manufacture of textiles.

[0120] The invention also relates to an aqueous composition thickened with a hybrid polymer (HP) according to the invention.

[0121] Other subject matter according to the invention

[0122] The invention also relates to a hybrid polymer (HP) comprising monomer units of at least one monomer comprising at least one unsaturated ethylenic function, and protein units, characterized in that the monomer units and the protein units are partially or totally linked by at least one covalent bond, in that the weight ratio between the monomer units and the protein units is between 50 / 1 and 1 / 5, preferentially between 25 / 1 and 1 / 3, more preferentially between 10 / 1 and 1 / 2, more preferentially between 6 / 1 and 1 / 1.

[0123] The invention also relates to a hybrid polymer (HP) obtained by free-radical polymerization according to a process comprising the following successive steps:(A) preparing a mixture (Ml) comprising at least one monomer comprising at least one unsaturated ethylenic function; and between 0.1% and 50% by weight of at least one protein, optionally at least one solvent;(B) initiating polymerization in the mixture (Ml) in order to obtain a hybrid polymer (HP).

[0124] The mixture (Ml) preferentially comprises between 5% and 90% by weight of at least one monomer comprising at least one unsaturated ethylenic function, more preferentially between 10% and 80%, more preferentially between 15% and 80%, more preferentially between 20% and 80%, more preferentially between 25% and 80%, more preferentially between 30% and 80%, more preferentially between 35% and 75%, more preferentially between 40% and 75%, more preferentially between 45% and 75%, more preferentially between 50% and 70%, more preferentially between 55% and 65%.

[0125] The mixture (Ml) preferentially comprises between 0.1% and 50% by weight of at least one protein, more preferentially between 1% and 40%, more preferentially between 3% and 35%, more preferentially between 5% and 30%, more preferentially between 10% and 25%.

[0126] The mixture (Ml) preferentially comprises between 1% and 90% by weight of at least one solvent, more preferentially between 5% and 80%, more preferentially between 10% and 70%, more preferentially between 15% and 60%, more preferentially between 20% and 50%.

[0127] The invention according to this other subject matter also relates to the use of the hybrid polymer (HP) described above as a viscosifying agent. It also relates to a viscosity modifying agent comprising at least said hybrid polymer (HP).

[0128] Generally, the polymerization is initiated by free radical initiators as presented in the present application; it can also be initiated by the action of UV radiation.

[0129] The polymerization is preferentially carried out in a temperature range extending from 20°C to 160°C, preferably from 30°C to 100°C.

[0130] The polymerization is preferably carried out in an inert gas atmosphere in the absence of atmospheric oxygen, for example using nitrogen or carbon dioxide as inert gas.

[0131] The reaction temperature and the amount of initiator generally have a significant effect on the polymerization of the hybrid polymer (HP).

[0132] Advantageously, the monomers comprising at least one unsaturated ethylenic function to be polymerized and the protein are introduced into the reaction vessel at the start with at least one polymerization initiator and polymerized by heating to the optimum polymerization temperature. It can be advantageous to use two or more proteins.

[0133] The order in which the reactants are dosed into the polymerization reactor can be freely modified. If a plurality of monomers are used in the graft copolymerization, the individual monomers can be dosed into the polymerization zone successively, or in the form of a mixture or else simultaneously from separate dosing means. For example, it is possible to heat a solution or dispersion of the protein in the reactor to the required polymerization temperature and to add the monomers and initiators continuously or in batches.

[0134] Similarly, the pH of the reaction medium can have an influence on the hybrid polymer (HP). The acidic or basic monomers can be used in the form of the corresponding salts. For example, acrylic acid is employed in the form of a free acid or in the form of an alkali metal salt. The polymerization can be carried out in a pH range extending from 1 to 14, preferably from 6 to 12. By modifying the pH it is possible, for example, to precipitate the graft copolymers from solutions. This possibility can be used during the treatment, the purification and the isolation of the graft copolymers.

[0135] The proteins used in the graft copolymerization may be chemically modified in various ways before or after the graft polymerization.

[0136] The DOSY experiment, NMR method, makes it possible to separate the species present according to their coefficients of diffusion in a solvent and makes it possible to analyse complex mixtures and detect traces. The aim of this experiment is to demonstrate that there is at least one covalent bond between the monomers comprising at least one ethylenic function and a protein. The DOSY experiment consists in recording proton spectra while varying the force G of the gradients applied and thus the diffusion force. A linear increase in the gradient strength will result in an exponential decrease in the NMR signal intensity. The DOSY experiment produces a two- dimensional map.

[0137] The second dimension F2 of the DOSY experiment corresponds, after Fourier transform processing, to the dimension 1H. The first dimension Fl corresponds to the decrease in the NMR signal as a function of the applied gradient force. After processing the dimension F2, the diffusion coefficient is extracted and a DOSY map is obtained. If the two matrices have an identical diffusion coefficient, this means that the two matrices have the same hydrodynamic radius, and are thereforegrafted. On the other hand, if the two matrices have two different diffusion coefficients, this means that they are free of one other.

[0138] In Figures 1 and 2, the NMR analyses were carried out on a Bruker 400 MHz ASCEND (TM) A vance III HD type apparatus equipped with a BBO 400 MHz Z-G radiating probe of 10 mm. TSP- d4 is deuterated sodium trimethylsilylpropanoate.

[0139] Conclusion:

[0140] The diffusion coefficient of the signals relating to the protein in the hybrid polymer differs from that of the protein alone (isolated).

[0141] NMR / DOSY (Diffusion Ordered Spectroscopy) analysis of the samples on pure products (products obtained after polymerization, and without additional treatment) made it possible to show that the protein is grafted onto the ATBS and that, subsequently, the unsaturated monomer is also grafted onto the oligomer.Examples

[0142] The examples which follow make it possible to best illustrate the advantages of the invention in a clear and non-limiting manner.

[0143] I - Synthesis of hybrid polymer according to the invention

[0144] Example 1 : HPA = ATBS homopolymer + casein

[0145] 450 g of tert-butanol comprising 2.5% by mass of water are introduced into a jacketed reactor fitted with a stirrer blade. 2-acrylamido-2 -methylpropanesulfonic acid (ATBS) is added with stirring. Gaseous ammonia is bubbled through the medium for 30 minutes, while checking that the pH does not exceed 7. The preparation is degassed in the reactor by injecting nitrogen for 30 minutes. During this time, the medium is gradually heated to 55 °C. Trimethylolpropane triacrylate (TMPTA, crosslinking / branching agent) is then added, followed by casein (milk protein) and the temperature of the medium is brought to 70°C using a thermostatically controlled bath. The polymerization reaction is initiated by adding 0.6 g of dilauroyl peroxide. The polymerization starts quickly and reaches an exothermicity maximum. Once the maximum temperature has been reached, the medium is refluxed for 2 hours.

[0146] The presence of a white precipitate in the solvent (tert-butanol + 2.5% by mass of water) is observed. This white precipitate corresponds to the hybrid copolymer of the invention. The solvent is then removed using a rotary evaporator with oil heated to 90°C and under a reduced pressure of 100 mbar. The copolymer obtained is then dried overnight at 70°C.

[0147] Table 1 below summarizes the composition of the polymer HPA as well as its viscosity.

[0148] The Brookfield viscosity is measured on a 1% by weight solution of polymer in water with a Brookfield RVT unit viscometer with a rotational speed of 20 rpm.

[0149] [Table 1]

[0150] Example 2: HPB = ATBS + acrylic acid copolymer + casein

[0151] The procedure is identical to that used in the example of hybrid polymer 1, except that the monomers used are 2-acrylamido-2-methylpropanesulfonic acid (ATBS) and acrylic acid (30 / 70 mol%). The polymerization reaction is initiated by adding 0.4 g of 2,2'-azobis(2- methylpropionamidine) dihydrochloride. The polymerization starts quickly and reaches an exothermicity maximum. Once the maximum temperature has been reached, the medium is refluxed for 2 hours.

[0152] Hybrid polymer 2 is recovered in the same way as above.

[0153] The amounts of protein and also of crosslinking agent can be modulated to achieve the desired viscosity and naturalness / biodegradability target.

[0154] Table 2 below summarizes the composition of the polymer HPB as well as its viscosity.

[0155] [Table 2]

[0156] Example 3: HPC = HPA without crosslinking agent

[0157] 450 g of tert-butanol comprising 2.5% by mass of water are introduced into a jacketed reactor fitted with a stirrer blade. 2-acrylamido-2 -methylpropanesulfonic acid (ATBS) is added with stirring. Gaseous ammonia is bubbled through the medium for 30 minutes, while checking that the pH does not exceed 7. The preparation is degassed in the reactor by injecting nitrogen for 30 minutes. During this time, the medium is gradually heated to 55°C. Micellar casein (milk protein) is then added and the temperature of the medium is brought to 70°C using a thermostatically controlled bath. The polymerization reaction is initiated by adding 0.6 g of dilauroyl peroxide. The polymerization startsquickly and reaches an exothermicity maximum. Once the maximum temperature has been reached, the medium is refluxed for 2 hours.

[0158] The presence of a white precipitate in the solvent (tert-butanol + 2.5% by mass of water) is observed. This white precipitate corresponds to the hybrid copolymer of the invention. The solvent is then removed using a rotary evaporator with oil heated to 90°C and under a reduced pressure of 100 mbar. The copolymer obtained is then dried overnight at 70°C.

[0159] Table 3 below summarizes the composition of the polymer HPC as well as its viscosity.

[0160] [Table 3]

[0162] The hybrid copolymers HPD to HPo are produced according to the protocol of Example 1.The polymerizations are carried out at 15% by mass of active material relative to the reaction medium The amounts of the various monomers are adjusted in order to obtain the proportions indicated in Table 4 below for each example.

[0163] [Table 4]

[0164] II - Application examples

[0165] Example 5: Textile application:

[0166] Pigmentary printing paste prepared in aqueous solution.

[0167] A pigmentary printing paste is produced at a viscosity of 6500 cPs, measured with a Brookfield RV unit viscometer at a speed of 20 revolutions per minute at 25 °C. The printing paste comprises: 12% of Helizarin 83 Liq C binder from the company Archroma (styrene / acrylic copolymer) or equivalent and 1.5% of a dispersion of the blue pigment PIGMACOLOR BLUE from the company KEMITEKS. The whole is mixed and hybrid polymer D of Example 1, as thickener, is then added with stirring to thicken the printing paste. The amounts of hybrid polymer D, and also of the other components, are adjusted in order to obtain the target viscosity of 6500 cPs.

[0168] Hybrid polymer D according to Example 1 and also two comparative examples outside of the invention are presented in Table 5 below: a thickening acrylic inverse emulsion and a thickening acrylic polymer obtained by precipitation polymerization (PA-PPP).

[0169] [Table 5]

[0170] The pastes produced are evaluated in terms of the application performance qualities of colourist yield, fixation and penetration, which are the major control parameters in screen printing.

[0171] The printing system is a FAM-R type printing table from the company Stork; the magnetic transfer doctor blade is a model with 10 mm diameter and 30 cm length and the printing frame is a model with 125 mesh aperture.

[0172] Three types of fabric are used to characterize the various parameters:- A 100% cotton canvas;- A 100% polyester satin and- A 97 / 3 cotton elastane satin.

[0173] After printing, the design is fixed by passing through a dryer for 3 minutes at 160°C.

[0174] The results are compared with each other under the judgement of a person skilled in the art.These results are recorded in Table 6 below.

[0175] [Table 6]0176] = : performance identical to the reference "inverse emulsion benchmark"

[0177] Reference: performance of the reference "inverse emulsion benchmark"

[0178] performance inferior to the reference "inverse emulsion benchmark"

[0179] — : performance far inferior to the reference "inverse emulsion benchmark"

[0180] Acrylic polymers obtained by precipitation polymerization are known to have application performance qualities that are inferior to the benchmarks obtained by inverse emulsion. For this reason, inverse emulsion thickeners are generally preferred in the world of screen printing.

[0181] Surprisingly, as can be observed, the hybrid polymer D obtained by precipitation polymerization according to the invention has printing performance qualities that are markedly superior to those of the "benchmark" acrylic (PA-PPP) obtained by a similar polymerization process. Moreover, the hybrid polymer D matches the benchmark obtained by inverse emulsion while having a lower consumption, which represents a definite advantage.

[0182] Example 6: Petroleum application:

[0183] A hybrid polymer HPp is produced according to the process according to Example 1. Its composition and its characteristics are specified in Table 7 below.

[0184] [Table 7]

[0185] Test for drilling application:

[0186] 600 g of G-Grade cement, 4.5 g of hybrid polymer HPp, 1.8 g of retarder (CR104), 1.2 g of dispersant (CD- IB) and 264 g of deionized water are added to a mixer. The whole is mixed for 15 seconds at a speed of 4000 rpm and then for 35 seconds at 12 000 rpm before being placed in a consistometer at 85°C for 20 minutes.

[0187] The fluid loss is then studied using an HTHP filter press at 85°C, under a pressure of 1000 psi over a period of 30 minutes. In the case of the benchmark, the fluid loss is 32 mL. In the case of the hybrid polymer, it is 38 mL. The latter is in good agreement with the required properties.

[0188] Example 7: Cosmetic application:

[0189] The following compositions comprise the hybrid polymer C or I, which are hybrid polymers obtained according to Example 1.

[0190] Table 8 below details an example of a cosmetic formulation comprising 1% by weight of hybrid polymers C and I.

[0191] [Table 8]

[0192] The cosmetic composition comprising the hybrid polymers according to the invention meets the cosmetic technical requirements with a target viscosity obtained.

Claims

Claims

1. Hybrid polymer (HP) in particulate form obtained by a free-radical precipitation polymerization process according to the following successive steps:(A) preparing a solution (SI) comprising:- 50% to 95% by weight of at least one polar solvent,- 4% to 40% by weight of at least one monomer comprising at least one unsaturated ethylenic function, and- 0.1% to 40% by weight of at least one protein; the percentages being given relative to the total weight of (SI), and totalling 100%;(B) initiating polymerization in the solution (SI) in order to obtain a dispersion (DI) comprising at least one hybrid polymer (HP), said polymer (HP) precipitating in the polymerization solvent;(C) isolating the hybrid polymer (HP), in particulate form, from the dispersion (DI).

2. Hybrid polymer (HP) according to Claim 1, characterized in that the solution (SI) is produced by first mixing the monomer(s) having at least one unsaturated ethylenic function and at least one polar solvent, and then subsequently adding the protein(s) to this mixture.

3. Hybrid polymer (HP) according to one of the preceding claims, characterized in that the monomer(s) comprising at least one unsaturated ethylenic function of step (A) are hydrophilic monomers.

4. Hybrid polymer (HP) according to Claim 3, characterized in that the hydrophilic monomer(s) are nonionic and / or anionic, such that when they are nonionic they are selected from acrylamide, methacrylamide, N,N-dimethylacrylamide, N-vinylformamide, N-vinylacetamide, N- vinylpyridine, N-vinylpyrrolidone, acryloylmorpholine (ACMO), diacetone acrylamide, or a mixture of these monomers, and when they are anionic they are selected from the group comprising monomers possessing a carboxylic acid function and salts thereof, monomers possessing a sulfonic acid function and salts thereof or monomers possessing a phosphonic function and salts thereof, or a mixture of these monomers.

5. Hybrid polymer (HP) according to one of the preceding claims, characterized in that the solution (SI) comprises from 10% to 30% by weight of at least one hydrophilic monomer, the percentage being given relative to the total weight of the solution (SI).

6. Hybrid polymer (HP) according to one of the preceding claims, characterized in that in step (A) the solution (SI) is prepared from a mixture of polar solvents and at least one monomer comprising at least one unsaturated ethylenic function, said mixture of polar solvents comprising 0.5% to 10% by weight of water, and at least 90% by weight of an alcohol comprising 1 to 4 carbons.

7. Hybrid polymer (HP) according to Claim 6, characterized in that the alcohol comprising 1 to 4 carbons is tert-butanol.

8. Hybrid polymer (HP) according to one of Claims 6 or 7, characterized in that the mixture of polar solvents comprises from 1% to 5% by weight of water and from 95% to 99% by weight of tert-butanol.

9. Hybrid polymer (HP) according to one of the preceding claims, characterized in that the protein is selected from proteins of animal origin, plant origin and / or mixtures thereof.

10. Hybrid polymer (HP) according to one of the preceding claims, characterized in that the protein is a casein, a serum protein, a wheat protein or mixtures thereof.

11. Hybrid polymer (HP), according to one of the preceding claims, characterized in that said hybrid polymer (HP) comprises monomer units of at least one monomer comprising at least one unsaturated ethylenic function, and protein units, said monomer units and said protein units being partially or totally linked by at least one covalent bond.

12. Hybrid polymer (HP) according to one of the preceding claims, characterized in that the hybrid polymer (HP) has a weight-average molecular weight of between 200 000 and 2 000 000 daltons.

13. Use of the hybrid polymer (HP) according to one of Claims 1 to 12 as a viscosifying agent in the recovery of hydrocarbons; in the drilling and cementing of wells; in the stimulation of hydrocarbon wells; in paper manufacture; in construction; in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; or in the manufacture of textiles.

14. Viscosifying agent comprising at least one hybrid polymer (HP) according to one of Claims 1 to 12, in the recovery of hydrocarbons; in the drilling and cementing of wells; in the stimulation of hydrocarbon wells; in paper manufacture; in construction; in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; or in the manufacture of textiles.

15. Aqueous composition thickened with a hybrid polymer (HP) according to one of Claims 1 to 12.

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